425

Filed by Towers Watson & Co.

Pursuant to Rule 425 under the

Securities Act of 1933, as amended,

and deemed filed pursuant to Rule 14a-6(b)

of the Securities Exchange Act of 1934, as amended

Subject Company:

Towers Watson & Co. (Commission File No. 001-34594)

The following is a press release issued by Towers Watson & Co. on November 20, 2015.

LOGO

Towers Watson Announces Adjournment of Special Meeting of Stockholders to December 11, 2015

ARLINGTON, Va. – November 20, 2015 – Towers Watson & Co. (NASDAQ: TW), a global professional services company, announced that today’s Special Meeting of Stockholders to vote on proposals recommended by Towers Watson’s Board of Directors regarding its proposed merger with Willis Group Holdings PLC (NYSE:WSH) has been adjourned to December 11, 2015 at 8:00 a.m. local time and will take place at The Westin Colonnade, 180 Aragon Avenue, Coral Gables, FL 33134. The Special Meeting of Stockholders has been adjourned in order to allow stockholders additional time to evaluate the amended merger agreement which was unanimously approved by the Towers Watson Board on November 19, 2015.

Under the amended merger agreement, the one-time cash dividend to be paid to Towers Watson stockholders will be increased to $10.00 per Towers Watson share. This dividend will be paid to Towers Watson stockholders of record three business days prior to the closing of the transaction. A complete copy of the amendment to the merger agreement has been filed with the Securities and Exchange Commission.

Towers Watson stockholders of record as of the close of business on October 1, 2015 will be entitled to vote at the Towers Watson special meeting on December 11, 2015. Stockholders who have already voted do not need to recast their votes. Proxies previously submitted will be voted at the reconvened meeting unless properly revoked. Stockholders who have not already voted or wish to change their vote are encouraged to do so using the instructions provided in their voting instruction form or proxy card.

Towers Watson stockholders, including employee stockholders, are reminded that their vote is important and are encouraged to complete, sign, date and mail the proxy card at their earliest convenience. Not voting or abstaining will have the same effect as a vote against the merger. Stockholders may also submit a proxy by telephone or via the Internet by following the instructions printed on the proxy card. If stockholders have any questions or need assistance with voting, please contact Towers Watson’s proxy solicitor, Mackenzie Partners, toll-free at (800) 322-2885.

About Towers Watson

Towers Watson is a leading global professional services company that helps organizations improve performance through effective people, risk and financial management. With 16,000 associates around the world, the company offers consulting, technology and solutions in the areas of benefits, talent management, rewards, and risk and capital management. Learn more at towerswatson.com.

Where You Can Find Additional Information

In connection with the proposed merger of Towers Watson and Willis Group, Willis Group filed a registration statement on Form S-4 with the Securities and Exchange Commission (the “Commission”) that contains a joint proxy statement/prospectus and other relevant documents concerning the proposed transaction. The registration statement on Form S-4 was declared effective by the Commission on October 13, 2015. Each of Towers Watson and Willis Group mailed the joint proxy


statement/prospectus to its respective stockholders on or around October 13, 2015. YOU ARE URGED TO READ THE JOINT PROXY STATEMENT/PROSPECTUS AND THE OTHER RELEVANT DOCUMENTS THAT HAVE BEEN OR WILL BE FILED WITH THE COMMISSION AS THEY BECOME AVAILABLE BECAUSE THEY CONTAIN OR WILL CONTAIN IMPORTANT INFORMATION ABOUT TOWERS WATSON, WILLIS GROUP AND THE PROPOSED TRANSACTION. You may obtain the joint proxy statement/prospectus and the other documents filed with the Commission free of charge at the Commission’s website, www.sec.gov. In addition, you may obtain free copies of the joint proxy statement/prospectus and the other documents filed by Towers Watson and Willis Group with the Commission by requesting them in writing from Towers Watson, 901 N. Glebe Road, Arlington, VA 22203, Attention: Investor Relations, or by telephone at (703) 258-8000, or from Willis Group, Brookfield Place, 200 Liberty Street, 7th Floor, New York, NY 10281-1003, Attention: Investor Relations, or by telephone at (212) 915-8084.

Forward-Looking Statements

This document contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995. You can identify these statements and other forward-looking statements in this document by words such as “may”, “will”, “would”, “expect”, “anticipate”, “believe”, “estimate”, “plan”, “intend”, “continue”, or similar words, expressions or the negative of such terms or other comparable terminology. These statements include, but are not limited to, the benefits of the business combination transaction involving Towers Watson and Willis Group, including the combined company’s future financial and operating results, plans, objectives, expectations and intentions and other statements that are not historical facts. Such statements are based upon the current beliefs and expectations of Towers Watson’s and Willis Group’s management and are subject to significant risks and uncertainties. Actual results may differ from those set forth in the forward-looking statements.

The following factors, among others, could cause actual results to differ from those set forth in the forward-looking statements: the ability to obtain governmental approvals of the transaction on the proposed terms and schedule; the failure of Towers Watson stockholders and Willis Group shareholders to approve the transaction; the failure of the transaction to close for any reason; the risk that the businesses will not be integrated successfully; the risk that anticipated cost savings and any other synergies from the transaction may not be fully realized or may take longer to realize than expected; the potential impact of the announcement or consummation of the proposed transaction on relationships, including with employees, suppliers, customers and competitors; changes in general economic, business and political conditions, including changes in the financial markets; significant competition; compliance with extensive government regulation; the combined company’s ability to make acquisitions and its ability to integrate or manage such acquired businesses. Additional risks and factors are identified under “Risk Factors” in Towers Watson’s Annual Report on Form 10-K filed on August 14, 2015, which is on file with the Commission, and under “Risk Factors” in the joint proxy statement/prospectus.

You should not rely upon forward-looking statements as predictions of future events because these statements are based on assumptions that may not come true and are speculative by their nature. Neither Towers Watson or Willis Group undertakes an obligation to update any of the forward-looking information included in this document, whether as a result of new information, future events, changed expectations or otherwise.


Contacts:

Investor Contact

Aida Sukys

aida.sukys@towerswatson.com

+1 703-258-8033

Media Contacts

Sard Verbinnen & Co

Michael Henson/Conrad Harrington

+44 (0) 20 3178 8914

Bryan Locke/Jenny Gore

+1 312 895 4700

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